Chapter 7
Cellular Repiration
ATP Makes the World Go ‘Round
• The main source of energy for all cell life is
ATP
• ATP = adenosine triphosphate
• ATP is made by the cell (mostly in the
mitochondria)
• ATP is made from the food we eat
• If your cells have no ATP, they cannot function
properly
The Basics
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Step 1: Glycolysis
– One glucose molecule enters the system
– Products are
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2 ATP
2 NADH
2 Pyruvate
Step 2: Formation of Acetyl Co-A
– 2 Pyruvate are consumed from step 1
– Products are
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2 NADH
2 CO2
2 Acetyl Co-A
Step 3: Krebs Cycle
– 2 Acetyl Co-A from step 2 are consumed
– Products are
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2 ATPs
2 FADH2
4 CO2
6 NADH
Step 4: Electron Transport Chain
– NADH and FADH2 from step 3 are consumed
– 34 ATP are produced
Cellular Respiration
• Cellular Respiration includes steps 3 and 4
– The Krebs Cycle
– The Electron Transport Chain
• This is an aerobic process
• This all happens within the mitochondria of
the cell
Fermentation
• Fermentation is an anaerobic process, just like
glycolysis
• When there is an absence of oxygen, ATP
synthesis continues through fermentation,
instead of cellular respiration
• Fermentation has been used to make alcohol,
cheese and many other products for centuries